Within the USS Yorktown, which serves as a floating museum at Patriot Point in South Carolina, there is a replica of the Apollo 8 capsule that went to the moon and back at Christmastime 1968.

The Yorktown was there -- 47 years ago -- to pick up the real Apollo 8 when it splashed down in the wide-open Pacific, carrying the first crew of human beings to ever circle the moon.

That was an American ship, manned by American sailors, picking up American astronauts, in an American century.

Nearby that Apollo 8 replica -- on the hangar deck of the Yorktown -- sit a number of propeller-driven aircraft, representing the warplanes that flew off U.S. aircraft carriers during World War II.

Together these flight machines point to the remarkable upward trajectory America followed in the first two and a half decades after that war.

The last Apollo spacecraft to reach the moon splashed down in December 1972 -- almost 43 years ago. Today, America shares something called the International Space Station with Russia and other nations. It sits in low Earth orbit.

Two generations of Americans have come of age in a nation that does not send men to the moon.

In 1968, when Apollo 8 took Americans on their first lunar orbit, 9.7 percent of the babies born in the United States, according to the CDC, were born to unmarried mothers. That was the last year when the percentage of American babies born to unmarried mothers was in single digits. In 2013, the latest year on record, it was 40.6 percent.

In January 1973, a month after the last Apollo moon flight, the Supreme Court declared that killing an unborn child was a "right." That year, America aborted 744,610 babies, according to an estimate by the Guttmacher Institute. Between then and 2014, National Right to Life estimates, America has aborted 57,496,011 babies. That is more than the entire population of this country, 50,189,209, from the 1880 census.

In 1968, according to the Census Bureau, the median household income for an American householder who had completed four years of high school but not gone to college was $52,025 in constant 2013 dollars. In 2013, it was $40,701. In the first 45 years post-Apollo 8, it dropped $11,324 -- or almost 22 percent.

In December 1968, while an American-manufactured space capsule was safely orbiting the moon, 18,410,000 Americans back on Earth were working in manufacturing, according to the Bureau of Labor Statistics. By December 2014, only 12,301,000 Americans were working in manufacturing -- a drop of 6,109,000, or 33 percent.

In 1968, according to the Bureau of Economic Analysis, the real Gross Domestic Product of the United States grew at 4.9 percent. The last time real GDP grew at that annual rate or higher was 1984, when it hit 7.3 percent. In the first 14 years of the 21st century, annual growth in real GDP has exceeded 3 percent only twice. The last time was a decade ago -- in 2005.

When the federal fiscal year ended on June 30, 1968, and the U.S. was preparing to send men to the moon, the federal government had a debt of $347,578,406,425.88. There were 60,938,000 households in the United States that month, according to the Census Bureau. Thus, the federal debt was approximately $5,704 per household. According the BLS inflation calculator that translates into approximately $38,803 in 2014 dollars.

By the end of fiscal 2014, on September 30 of last year, the federal debt was $17,824,071,380,733.82, and there were 115,831,000 households in the United States. Thus, the federal debt equaled about $153,880 per household -- or about four times what it was when Apollo 8 splashed down.

And the decline we are facing is measurable not only in lost lives and material well-being.

In a column this week, Pat Buchanan cited a Pew Research Survey on the decline of religion in America. "Whereas 86 percent of Americans in 1990 identified as Christians, by 2007, that was down to 78 percent," Buchanan wrote. "Today only 7 in 10 say they are Christians. But the percentage of those describing themselves as atheists, agnostics or nonbelievers has risen to 23."

It is not a spaceship that is now dropping out of orbit; it is our country.

America has never been a perfect nation, but it has always been a great one. That greatness was rooted in a pioneering spirit, propelled by faith in God, family and self-reliance.